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The billing model map

Four concept pages describe the same prepaid-money arc from different angles, and until now nothing said which one to open for a given question. This page is that index. Resolve your question here, then jump straight to the page that owns the answer — without reading four pages to find the one rule you came for.

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The four billing-concept pages, one question each

Everything else on the money arc — the pause and gate chains, the rate-resolution family, the documents and attribution pages — hangs off those four. The rest of this page maps each of them onto the family it belongs to and puts a “which page owns” table at the bottom for the questions readers actually confuse.

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The wallet-ledger family

  • Wallets, credits, and charges is the ledger itself. It owns the append-only credit/debit model, the pause bits that gate outbound sends, the idempotency keys that make a retried debit safe, the integer micro-cent units every balance figure is stored in, and the degraded-balance fallback.
  • Usage metering pipeline owns the send → usage record → rollup chain end to end. It also owns the metering-vs-billing boundary (metering measures; billing prices) and the re-derivation guarantee — every rollup can be replayed from the raw records.
  • Billing and wallet owns what happens to a usage event when it crosses that boundary: the rating pipeline that prices it against included quantity and graduated tiers, the FX source pipeline for converted top-ups, tax handling, and the authorize-before-use contract.
Read these three in that order when you are onboarding onto the billing surface; the fourth page of the family, usage records model, is the reconciliation lens back down to row level.

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The usage-record → rollup → invoice chain at a glance

  1. A send completes (message out, or a call ends). Metering writes one append-only usage record with the billed units.
  2. The rating pipeline prices the record against the resolved rate and any tiers or surcharges in force.
  3. Rollups aggregate the priced records into the figures the invoice or statement is built from.
  4. The invoice (billing provider) or statement (wallet ledger) renders from those rollups — see billing documents model.
The owner for steps 1–3 is usage metering pipeline; the owner for step 4 is billing documents model. The row-level feed underlying step 1 is usage records model.

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The pause/gate chain family

Balance-driven pauses and account-lifecycle holds are deliberately separate pages; the chain they both sit in has its own page.
  • Billing gate chain model — the ordered chain every outbound send walks before funds move: pre-flight balance check, pause/block flags gate, per-channel fund path, atomic check-and-decrement. Per-surface zero-balance behavior lives here.
  • Outbound pause and the free-channel exemption — why a balance-driven pause bypasses $0-price channels like WhatsApp while an account-lifecycle hold blocks every channel.
  • Two-phase billing lifecycle — the authorize / capture / release lifecycle for flows that reserve funds before they run, versus the synchronous charge path.
  • Committed-use drawdown model — the enterprise monthly commitment meter: where the commitment lives, how to read the drawdown and run-rate projection, and why the meter degrades to a hidden panel instead of an error.

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The rate-resolution family

Every rating decision resolves through one precedence ladder. The main ladder page and the layer-specific pages are:
  • Pricing and rate resolution — the SMS price precedence ladder: a verbatim per-operator override ahead of organization markup ahead of the platform-default markup, plus the no-published-rate case.
  • MCC/MNC override model — the per-(organization, operator) override record that binds one network to one fixed price, applied verbatim ahead of every markup rule.
  • Volume-tier resolution model — graduated rates that apply themselves at debit time from a monthly usage counter.
  • All-in pricing: surcharges — the itemized surcharge menu (registration, recording, transcription, premium support) stacked on the resolved base rate.
  • What-if pricing model — the money-free simulator that re-prices your recorded usage lanes against a candidate rate card. Ends where live rate resolution begins.
  • Reseller margin and the tax pipeline — the per-subaccount margin applied before tax, and why it lands on ledger descriptors rather than the wallet.
  • Pricing-preview pipeline — the five read-only preview endpoints that project a billing period before it closes, and how they differ from the ledger, the invoices, and the what-if simulator.

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The money-adjacent family

Pages that the billing surface depends on without being part of the rating or ledger:
  • Billing documents model — what invoices, statements, and recurring-agent subscriptions each mean, and why statement balances reconcile through the wallet.
  • Spend anomaly and alert model — threshold alerts, burn-rate projection, and automatic velocity-anomaly detection, with the anomaly ledger behind them.
  • Cost channel rollup model — why the Insights “Costs by channel” totals legitimately differ from the ledger totals, and how to reconcile them per period, channel, and currency.
  • LLM spend cost attribution model — the feature × model × conversation attribution axes behind the AI-spend surfaces and the conversation P&L view.
  • Billing API reference and the usage metering API reference — the endpoint-level surface for wallets, usage records, and rollups. Concept pages explain the model; the API reference names the endpoints and fields.

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Which page owns the question? The five most-confused cases

Ledger idempotency keys belong to wallets, credits, and charges; pause semantics belong to the gate chain; usage metering as a pipeline belongs to usage metering pipeline; and rating belongs to billing and wallet. If your question is not in the table, pick the family above and open the page whose one-line question matches yours.

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See also